Unlike other nonhuman primates—including our other closest living relatives, chimpanzees—peace-loving bonobos seem to tolerate strangers, share resources with random bonobos, and exhibit a form of empathy called contagious yawning. (Related: "'Contagious' Yawning Occurs More Among Loved Ones.")

These findings may help to solve the long-standing evolutionary puzzle of why humans show kind or helpful behavior to other humans beyond their immediate family or group: It could have a biological basis.

"Certainly culture and education play an important role in the development of human altruism, but the bonobo finding tells us that even the most extreme form of human tolerance and altruism is in part driven by our genes," Tan said.

Fair Share

The team has set up various experiments with the sanctuary bonobos to test their willingness to share.

In another experiment, Hare and Tan discovered that bonobos also have a humanlike habit of "catching" yawns from strangers—again, the only nonhuman primate known to do this.

As with sharing with strangers, contagious yawning can be seen as an expression of empathy.

Bonobos Becoming Bushmeat

But our altruism apparently isn't extended to our nearest primate cousins: Due to human activities, fewer than 20,000 bonobos are thought to remain in their home range in the Congo Basin, and their numbers continue to fall. The International Union for Conservation of Nature lists the species as endangered.

A growing threat to their survival is the illegal trade in great apes to Asia. Tan also highlighted the superpower's growing presence within Africa, which includes one million Chinese nationals.

Hare said that animals are being sold for $50,000 to $300,000 each to zoos, circuses, and private individuals in China.

"We have seen growing reports that Chinese consume bushmeat in Africa, keep pet chimps in Africa, and also there is this illegal ape trade," Tan said.

Her view is echoed by Jo Thompson, executive director of the Lukuru Wildlife Research Foundation, based in Kinshasa. "The pervasive threat across the whole of the wild population is the demand for bushmeat," Thompson said.

Getting to Know the Bonobo

Even so, Hare and Tan hope that by publicizing bonobo behavioral studies in countries like China, scientists can help to raise the profile of this caring, sharing primate.

The team will also be promoting bonobo conservation in person this fall, when they head to eastern China to teach at Duke Kunshan University.

Said Tan: "There are many examples that great conservation efforts starts with the public getting to know the scientific discoveries about how amazing a species is."